Oscillations



May 1; 1923. 1,453,584

' J. BLANKENBURG DEVICE FOR XMFLIFYING TELEPHONE CUHRENTS AND OTHER ELECTRIC OSCILLATIONS Filed June 17, 1 919 2 Sheets-Sheet 1 m mvm? dam/m! aun/lriweukd May 1, 1923. .1. BLANKE'NBURG DEVICE FOR AMPLIFYING TELEPHONE CURRENTS AND OTHER ELECTRIC OSCILLATIONS Filed June 17, 1919 2 Sheets-Sheet 2 Patented May 1, 1923.

PATENT OFFICE.

:orumims smxsnnono, or BERLIN, GERMANY, ASSIGNOB, BY HESNE ASSIGN stazrrs,..:ro .zusmnoozs ,vmmoorscnar FINANZIEELE maa'rscmm "mm;- a. mm," onms'rs umm, NETHERLANDS, A COMPANY or THE NETHERLANDS.

omen roit mruryms rstsrnons commn'rs aim mm miso'rmooscnmamons- Application filed June 17, m9. Serial No. amass.

' Toauwlwm it may concern:

Be itknown that I. Jonaxxss lhaxmzxnURorsiding at Berlin. Get-litany. have iniietited certain new and useful Improve ment s iniDevices for Amplifying Tele hone Cui'rents and Other Electric Oscillations. f which the following is a specification.

W Thegprsent invention relates to an armag'e nvfor amplifying telephone currentsahd'oth'er electric oscillations in which thearinature 0ft). magnetic system. the magnetiofield of which is varied by the said -g lectric oscillations, is coupled to a microphone. The new arrangement differs from the jsiniilar arrangementsheretofore disclosed essentially in the arrangenient of the armature and its coupling with the movable electrode of the microphone. which likewise is disposed in a novel manner. Further novehfatures, which consist in the combination of various arrangements, will become ap atent from the following specification.

einventionhas been exemplified in a "oonstructional form in Fig. 1 of the act-our $5 panying drawings. Fig. 2 is a section alon theline'Q-2 of Fig. 1. Fig. 3 is a section along the line 33 of Fig. 1. Fig. 4- is a detailed view of the abutment in front elevation; Figs. 5 and 6 disclose a modified formofFigs. 1 and 2, Fig. (i being a section on line 66 of Fig. 5. Fig. 7 shows the. abutment corresponding to Fig. 4 in front elevation according to the modification shown in- Figs. 5 and 6. Fig. 8 is a plan of u the connections preferable for the new on rangement. On the underside of a bascplate 1 is fitted, as me telephone receiver, a magnetic magazine consisting of three permanent magnets 40 2. To the pole ends are fitted in known fihanner pole shoes 3 which are bent at an acute" angle in such a manner that the pole surfaces converge. Each of these pole shoes is'fitted with an electromagnetic coil 4. the windin of which are connected with each other on one side. and at the other side are connected to the terminals 5. Between the pole surfaces. is disposed the armature (i. which is made relatively thick and stitT (rigid), and of such a shape that it forms a veryshort bridge for the lines of force from the one to the opposite pole. The armature thus extends transversely of the bears through themedium ofja ton'gu'efll.

The hinge bearing is composed of,a;brac ket in which the boss 7 of the art st-unis; supported by means of centerscrews 8, 'At the other end the tongue 9, made .of a more or less elastic material, is fitted, which tongue will. under influen e of a mtugfnetiov attraction of the armature toward the poles, bear against an abutment- 10. This abutment 10 is fitted to a bracket 11, at the. top of which a rod is fitted into a. bore 34. This rod has at its one end a fitting 36 adapted to receive a pad 3 7 of a suitable elastic material such as rubber, leather. felt or the like, whichis dovetailed therein. ,Against this pad 37 bears the tongue 9 of the armature 6. For allowing, adjustment of the armature relatively to. the pole surface. the abutment itself is made adjustable. This adjustability of the a'rmaf ture may be obtained in any suitable man: nor. in the arrangement shown {in the drawing. the position of tin rod mayfbejjti varied by means of a coiled spring 38and -a set screw 39 fitted in a coller 40 secured. to bracket 11. whereby the armature may be set relatively to the pole surfaces. In place. of the elastic pad 37, a knife edge may be employed as an abutment, as shown in igs. 5. 6 and 7. As may be seed from Fig. 7. the knife edge lti'is clovetailed to a small plate 12. This plate 12 may be'adjusted in a guide on the bracket 11 in a parallel sense so as to vary the width of the gap between the armature and the poles. The adjust? ment may be secured by means of ascrew 13. To the armature (i is fitted a rod -14 which extends through the base plate-1 and forms the coupling between the magnetic svstem just described and the microphone 15 arranged on the other side of the base plate 1. This microphone is so supported by means of several brackets 23 that it is turned with its movable electrode toward the base plate 1. It may consist in known manner of a box 16, to the bottom of which a carbon block 18 is secured, insulated therefrom by means of an intermediate disc 17 of insulating material. This carbon block is provided with the carbon cells 19 and .is conductivelv connected with the terminal screw 20. Parallel to the face of the carbon cells is disposed a disc 21 as a movable electrode. This disc may be secured in a known manner to the rim of the box 16, and would perform only such oscillations as consist'in a vibi'ation of the center of the membrane; In the drawing the disc 21 is of a smaller-diameter than the box 16, so that it isnot clamped to the'rim of the latter. The"disc 21 is therefore absolutely free and may'ioscillate in a parallel sense without any de formation, The disc 21 is held by means of='a socket 22, into which the coupling rod 14 is secured by means of a set screw." The carbon cells are filled with carbonballs', and form the microphone contact between the carbon block 18' and the disc 21. fTheelcctric connection to the disc 21 is formed by the coupling rod 14 and the socket 22. v The the bracket 25 forarmature 6,

terminal screw 24 is arranged on one side of bracket 25. A number of hooks 26 may also be provided on the box 16 for holding or retainin the disc 21.

For limiting the stroke of the armature 6, the latter is rovided with a rear support at its center. or this purpose a bridge 30 is disposed across the magnet system, the bases 31 of which bridge bear on the ears of the poleshoes 3. In the center of this bridge 30 is disposed a set screw 32 fitted with a ad 33 of an elastic material bearing against the armature 6. The object of this arrangement is to limit the stroke of the armature in case the armature should be forced by some outward force away from the les of the magnet contrary to the action of the'latter, as the carbon balls mi ht in such case fall out from their cells, so t at the whole device would become absolutely useless. The siipport 32 with its soft pad 33 has the further object of deadening the individual oscillation of the armature which may occur in some devices. For this purpose the set screw32 is set in such a manner that its soft pad bears against the rear of the armature and thereby cushions the latter.

The device described operates in the following manner: The armature 6, which is supported by the hing: bearing on bracket 25 and the abutment aring' 10, or by two such abutment bearings, the same as a beam on two supports, is under uniform action of the magnetic field. The stillness of the tongue 9 permits the armaturelby a corresponding adjustment of the abutment 10, which mav. according to circumstances have a hard or soft pad,to be approached to the smallest possible distance from the poles of the electronia et without the armature being complete y drawn up to the oles of the magnet' Thereby it is rendered impos sible for the armature 6 to stick to the poles, which would cancel the action of the amplitying relay. On the other hand, this adjustability of the gap between armature and poles, rendered possible by :1 stiff and strong tongue 9, will greatly increase the sensitiveness of the amplifying relay, as the same increases by the uare with the reduction of the said gap. wil v to the very small magnetizin forces cite current im ulses to be amp ified this arrangement wi Lad mit of an extremely strong efl'ect, bythe armature answering, in consequence of its being set to the smallest'gap" circuit into which the said microphone is,

connected.

ssible,- to the A finest arriving electric oscilations, which are then transmitted to 'the movable elec The leads for the oscillations to be amplified are connected, see Fig. 8, to the terminals 5 of the magnet windings, 4. The mi crophone is connected at 20.nnd 24 into a circuit, which contains a battery 27am! an inductiou coil or transmitter 28. The current flows from the terminal 20 over the carbon block 18 and the carbon cells 19 to the disc 21, thence overthe socket 22 and the coupling rod 14, the armature 6, the hearing at 7 and the bracket 25 to the terminal 24. From the other winding of the induction coil the leads 29 proceed for theamplified currents. of these devices may be connected either in series or in multiple are behind each other,

the leads 29 in such case being connected to For increasing the efl'ect, several 1. In a device for amplifying telephone currents and other electric oscillations a polarized'magnet s stem, the magnet field of which is varied y the electric oscillations, an elongated armature comprising 'a relatively thick and rigid ortion dis in front of the poles of said polariz magnet system and a relatively elastic portion at a greater distance from said poles, a. bearing for said armature at each of its ends contrary to the action of the magnetic force of the polarized field, a transmitter, and a conplin of the movable electrode of the trans mitt with the said armature, the connection of said coupling to the armature being closer to the point at which the magnetic force of said polarized magnet system not! 2. In a device for amplifying telephone eases g currents and other electric oscillations, a armature bears contrary to the attraction of polarized magnet system, the magnetic field the magnet system, a transmitter, a coupling an of which is varied by'the electric oscillations, rod fitted at its one end to the movable elecan armature dis in front of the poles trade of the transm'tter and at its otherend of s'aid la' 7 magnet system, on the one to the said armature closer to the point at end of t armature a hinge bearing, on the which the magnetic force of said pola other end-of the armatnre an elastic tongue, magnet system acts than to said abutment an abutment bearing aginst which the bearing. tongue 'of the armature are contrary to 4. In a device for amplifying telephone W the attraction of the magnet system, a transcurrents and other electric oecillatio a mitter; 'a ooi'i'pling between the movable polarized magnet system, the hold of. ch 7 electrode of e transmitter and the said 18 varied by the electric oscillations, 46 armature, the connection of said coupling to armature disposed in front of the poles 1 the armature being closer to the point at said magnet system, a hinge bear-law which the magnetic force of said polarized endof said armature, an

t magnetic system acts than to said hinge which a toii le on the other endo' bearing. v t e 8. In a dei'ioe for amplifying telephone said magnet "s stem,t means for currents and other electric oscillations, a said abutmdnt aring for varying t e P polarized magnet system compomd of a set between sdid armature and the magnet of permanent magnets'and two converging a transmitter, and a coupling between t pole shoes on which the electromagnetic movable electrode of the transmitter and 66 coils are fitted and through whichthe electhe armature of the ma at system oon between said pole -shoes and across the path at w oh the force of said magnet trio oscillations flow, an armature, disposed n y said armature c os er to the oint of the lines o forceof said magnet system, so than to either of the bearing! 0 said a eorthat it'fills' the angle formed by the cona mature. 00 var g pole shoes and forms a very'sho In testimon whereof I ailix my signature hri forvthe magnetic lines of force in presence 0 two witnesses.

one pole to the other, a hinge bearing the J OHANNES BLANKENBURGQ one end of the armature, an elastic to gue on With: the other end of the armature, an utment Enrrn Wm, bearing against which the tonzue of the HIIRHANNPRIWII armature bears ntrary to the action of 80; 

